1. Field of the Invention
The present invention relates to a water tank and a refrigerator having the same, and more particularly, to a water tank for supplying water, temporarily stored therein, to an ice maker without leakage of the water, and a refrigerator having the same.
2. Discussion of the Related Art
Generally, refrigerators are electric appliances for keeping foods in a fresh state by freezing or cooling the foods, and usually include a freezing chamber and a refrigerating chamber. Further, an ice maker for making ice is provided in the freezing chamber.
FIG. 8 is a front view illustrating the internal structure of a conventional refrigerator, FIG. 9 is an exploded perspective view of a water tank provided in the refrigerator of FIG. 8, and FIG. 10 is a longitudinal sectional view of the water tank in a state in which the water tank is installed on a door of the refrigerator of FIG. 8.
As shown in FIGS. 8 to 10, a freezing chamber 11 and a refrigerating chamber 13 are provided in a main body 10 of a conventional refrigerator, and a freezing chamber door 11a and a refrigerating chamber door 13a are rotatably installed on the main body 10. The freezing chamber door 11a and the refrigerating chamber door 13a serve to selectively open and close the freezing chamber 11 and the refrigerating chamber 13, respectively.
A plurality of door baskets 14 for receiving foods are detachably installed on the rear surfaces of the freezing chamber door 11a and the refrigerating chamber door 13a, and home bars 15 and 16, through which ice and beverages can taken into and out of the refrigerator without opening the freezing chamber door 11a and the refrigerating chamber door 13a, are respectively provided in the freezing chamber door 11a and the refrigerating chamber door 13a. 
First and second ice maker housings 17 and 19 are provided on the freezing chamber door 11a at a designated position above the home bar 15, and an ice tray (not shown) for making ice is installed in the first ice maker housing 17. An ice bank (not shown) for taking the ice, made by the ice tray, out of the refrigerator through the home bar 15 is installed in the second ice maker housing 19.
A mounting space is formed between any one of the door baskets 14, installed on the rear surface of the freezing chamber door 11a, and the first ice maker housing 17, and a water tank 21 is detachably installed in the mounting space. The water tank 21 stores water, which will be supplied to the ice tray. As shown in FIG. 9, the water tank 21 includes a tank main body 22, a tank cover 23, a supply hole cover 24, and a valve 25.
The tank main body 22 has a polyhedral shape, the upper portion of which is opened, and a water storage space 22s for storing a designated amount of water is provided in the tank main body 22. A support protrusion 22a is provided on the inner surface of the edge of the tank main body 22, and a knob part 22b, which is held by user's hand so as to attach and detach the water tank 21 to and from the mounting space, is provided on one side of the lower surface of the tank main body 22.
A guide groove 22c for guiding the water tank 21 is formed in the lower surface of the tank main body 22 by upwardly indenting a part of the lower surface of the tank main body 22, and a guide rib 17a provided on the upper surface of the first ice maker housing 17 is inserted into the guide groove 22c. 
The tank cover 23 is connected to the upper portion of the tank main body 22 so as to selectively open and close the water storage space 22s, and the edge of the lower surface of the tank cover 23 is supported by the upper surface of the support protrusion 22a. A supply hole 23h for supplying water from an external water source to the water storage space 22c is formed through a designated position of the tank cover 23, and a packing groove 23a surrounding the supply hole 23h is formed in the upper surface of the tank cover 23.
A receipt stage 23b, on which the supply hole cover 24 is laid under the condition that the supply hole cover 24 closes the supply hole 23h of the tank cover 23, is formed on the upper surface of the tank cover 23. The receipt stage 23b is obtained by stepping a part of the tank cover 23 including the supply hole 23h and the packing groove 23a. 
A knob groove 23c, into which a user's hand is inserted, for rotating the supply hole cover 24 against the tank cover 23 is formed in the upper surface of the tank cover 23, and a contacting protrusion 24a and a packing protrusion 24b are provided on the lower surface of the supply hole cover 24. Under the condition that the supply hole cover 24 closes the supply hole 23h of the tank cover 23, the outer circumferential surface of the contacting protrusion 24a contacts the inner surface of the supply hole 23h, and the packing protrusion 24b is inserted into the packing groove 23a. 
With reference to FIG. 10, a discharge hole 22h for supplying the water stored in the water storage space 22 to the ice tray is formed through a designated position of the lower surface of the tank main body 22. The discharge hole 22h is connected to a water supply hole 17h formed through the upper surface of the first ice maker housing 17 under the condition that the water tank 21 is installed in the above mounting space, and an insertion rib 22r is provided on the lower surface of the tank main body 22 corresponding to the circumference of the discharge hole 22h. 
The valve 25 includes a valve bracket 26, a valve main body 27, a packing ring 28a, and a first elastic member 29. The valve bracket 26 is provided along the circumference of the discharge hole 22h of the tank main body 22, and a water supply hole 26h for substantially supplying the water stored in the water storage space 22s to the ice tray therethrough is formed through the valve bracket 26.
A receipt groove 26a is formed in a designated position of the upper surface of the valve bracket 26 adjacent to the water supply hole 26h, and the outer circumferential surface of the packing ring 28a is laid on the receipt groove 26a. 
An insertion groove 26b, into which the insertion rib 22r of the tank main body 22 is inserted, is formed in the upper surface of the valve bracket 26, and a fixing hook 26c, which is caught by the bottom surface of the tank main body 22 under the condition that the insertion rib 22r is inserted into the insertion groove 26b, is provided on the upper surface of the valve bracket 26 inside the insertion groove 26b. 
The valve main body 27 passes through the water supply hole 26h of the valve bracket 26, and is vertically movable. When the water tank 21 is installed in the mounting space, the valve main body 27 moves upwardly by means of a driving protrusion (not shown) provided on the upper surface of the first ice maker housing 17, and thus opens the water supply hole 26h of the valve bracket 26.
An insertion groove 27a, into which the inner circumferential surface of the packing ring 28a is inserted, is formed in the upper end of the valve main body 27, and a flange part 27f, the upper surface of which supports one end of the first elastic member 29, is provided on the lower end of the valve main body 27. A water supply hole 27h is formed through a position of the flange part 27f corresponding to the water supply hole 26h of the valve bracket 26.
A packing member 28b is provided between the insertion rib 22r of the tank main body 22 and the insertion groove 26b of the valve bracket 26, and both ends of the first elastic member 29 are respectively supported by the lower surface of the valve bracket 26 and the upper surface of the flange part 27f of the valve main body 27.
The above-described conventional water tank and the refrigerator having the same, have several problems, as described below.
The valve main body 27 moves upwardly by means of the driving protrusion provided on the upper surface of the first ice maker housing 17 and thus opens the water supply hole 26h of the valve bracket 26. Thereby, the water stored in the water storage space 22s is supplied to the ice tray through the discharge hole 22h of the water tank 21.
Accordingly, when the valve main body 27 moves upwardly by means of the driving protrusion and thus opens the water supply hole 26h of the valve bracket 26 under the condition that the water tank 21 is not completely installed in the mounting space, the water stored in the water storage space 22s may leak out through the discharge hole 22h of the water tank 21.